Abstract

A 2-year investigation into shoreface morphodynamic behaviour off a high-energy headland-embayment coast in Northern Ireland reveals important process-response mechanisms that cannot be explained solely by existing conceptual models. A comparison of 14 sequential bathymetric surveys, from 1 to 24 m water depth, shows that the Portstewart shoreface is in equilibrium with modal to high-energy conditions; significant morphologic change is generally associated with summer and/or fair-weather conditions. Additionally, antecedent morphology appears to be a primary control on subsequent behaviour; shoreface areas that had accreted in the previous survey period were more likely to erode. Also, the high-energy shoreface and beach appears to be in a state of accretion over the survey period, which is consistent with a falling late Holocene relative sea-level, a linear and dissipative shoreface profile and an abundance of sand in the coastal system. (C) 2009 Published by Elsevier Ltd.